I Feel like this is a no brain-er that players should be able to access their inventory when in a vehicle. Obviously limiting what items can be used while in the vehicle to single handed; non-weapon items, I.E. ready to eat food, single handed water containers, compass, map, handheld optics, first-aid items, activating night vision and as well as various other items that make sense.
this thought only really crossed my mind after finding a car and driving it, needed to eat and being a little frustrated by having to come to a complete stop, getting out, scarfing down a whole uncooked pepper and getting back in.
If this is too much to ask, at the vary lease allow items in the players hot bar to be used. (Abiding by the same limitations previously mentioned).
Also give cars turn signals with Z and X, because I think it would be funny.